Fundamentals of Sample Preparation for Environmental Analysis - Fundamentals of Environmental Sampling and Analysis - page 169

Figure 7.4 Liquid-liquid
(L-L) extraction:
(a) Conventional separatory
funnel L-L extraction
(Courtesy of Kimble Glass
Inc.) (b) Continuous L-L,
heavier than water extraction,
and (c) Continuous L-L, lighter
than water extraction (Courtesy
of Kontes Glass Company)

(a) (b) (c)

Solvent Density and Immiscibility The density difference is needed for a
phase separation. The need for immiscibility of two phases is also apparent. For
instance, water miscible solvents such as acetone, methanol, ethanol cannot be used for
L-L extraction. Figure 7.5 is a solvent miscibility chart. One should be able to use this
chart to explain which solvents can or cannot be used in L-L extraction if, for example,
aqueous phase samples are to be extracted.

Immiscible Miscible

Figure 7.5 Solvent miscibility chart (Sadek, PC, 2002, Reproduced with Permission, John Wiley &
Sons Limited)